Background: Atrial fibrillation (AF) causes electrical, functional, and structural changes in the atria. We examined electrophysiologic remodeling caused by AF and its reversal noninvasively by applying a new atrial signal analysis based on magnetocardiography (MCG).
Methods: In 26 patients with persistent AF, MCG, signal-averaged electrocardiography (SAECG), and echocardiography were performed immediately after electrical cardioversion (CV), and repeated after 1 month in 15 patients who remained in sinus rhythm (SR). Twenty-four matched subjects without history of AF served as controls. P-wave duration (Pd) and dispersion (standard deviation of Pd values in individual channels) and root mean square amplitudes of the P wave over the last 40 ms portions (RMS40) were determined.
Results: In MCG Pd was longer (122.8 +/- 18.2 ms vs 101.5 +/- 14.6 ms, P < 0.01) and RMS40 was higher (60.4 +/- 28.2 vs 46.9 +/- 19.1 fT) in AF patients immediately after CV as compared to the controls. In SAECG Pd dispersion was increased in AF patients. Mitral A-wave velocity and left atrial (LA) contraction were decreased and LA diameter was increased (all P < 0.01). After 1 month, Pd in MCG still remained longer and LA diameter greater (both P < 0.05), while RMS40 in MCG, Pd dispersion in SAECG, mitral A-wave velocity, and LA contraction were recovered.
Conclusions: Magnetocardiographically detected atrial electrophysiologic alterations in persistent AF diminish rapidly although incompletely during maintained SR after CV. This might be related to the known early high and late lower, but still existent tendency to AF relapses.